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41.
Summary Time-dependent perturbation theory has been applied to calculate the doubly excited triplet statesNsns:3Se,Npnp:3De andNdnd:3Ge (N=2, 3, 4,n=N+1, ... ,5) for He, Li+, Be2+ and B3+. A time-dependent harmonic perturbation causes simulataneous excitation of both the electrons with a change of spin state. The doubly excited energy levels have been identified as the poles of an appropriately constructed linearized variational functional with respect to the driving frequency. In addition to the transition energies, effective quantum numbers of these doubly excited states have been calculated and analytic representations of their wave functions are obtained. These are utilized to estimate the Coulomb repulsion term for these states which checks the consistency of the wave functions. These wave functions may also be used for calculating other physical properties of the systems. 相似文献
42.
Ghosh SK Hossain SU Bhattacharya S Bhattacharya SC 《Journal of photochemistry and photobiology. B, Biology》2005,81(2):121-128
The compound 2-(2-selenocyanic acid ethyl ester)-1H-benz[de] isoquinoline-1,3-(2H)-dione (SEBID), a ubiquitous, bioactive naphthalimide derivative is expected to possess an anticancer, anti-tumor and other important therapeutic activities of significant potency with low systematic toxicity. In this paper, the synthesis of the compound, photophysics of the newly prepared naphthalimide derivative and its interaction with model transport protein Bovine serum albumin (BSA) have been reported using the absorption and steady state fluorescence spectroscopic techniques exploiting the intrinsic fluorescence emission properties of BSA as a probe. Interaction of this organoselenium compound in different dioxane-water mixtures with increase in the polarity of the medium has been studied spectroscopically. Interaction of SEBID with BSA leads to a dramatic decrease in the fluorescence intensity of BSA, which suggests the binding of SEBID with the tryptophan residue of BSA. Furthermore, different thermodynamic parameters for SEBID-BSA interaction have been calculated. Rationalization of the data has been attempted, particularly in relation to prospective applications in the biomedical research. 相似文献
43.
Solution polymerization of MMA, with pyridine as the solvent and BZ2O2 and AIBN as thermal initiators, was studied kinetically at 60°C. The monomer exponent varied from 0.45 to 0.91 as [BZ2O2] was increased from 1 × 10?2 to 30 × 10?2 mole/liter in a concentration range of 8.3-4.6 mole/liter for MMA. For AIBN-initiated polymerization the monomer exponent remained constant at 0.69 as [AIBN] varied from 0.4 × 10?2 to 1.0 × 10?2 mole/liter in the same concentration range for MMA. The k2p/kt Value increased in both cases with an increase in pyridine concentration in the system. This was explained in terms of an increase in the kp value, which was due presumably to the increased reactivity of the chain radicals by donor-acceptor interaction between the molecules of solvent pyridine and propagating PMMA radicals and in terms of lowering the kt value for the diffusion-controlled termination reaction due to an increase in the medium viscosity and pyridine content. 相似文献
44.
Summary The conditions for the formation of revert type ofLiesegang rings have been studied here. Various systems of rhythmic precipitations of silver chromate are produced in a mixtures of
agar and gelatin gels under different environmental conditions. Ring systems of silver, copper and other ferricyanides have
also been studied in gelatin gel. The observations show that the cause of the revert systems ofLiesegang rings is the high peptizability of the precipitating matter in the media containing gel and the unreacted ions.
Zusammenfassung Die Bedingungen der Bildung des „umgekehrten“ Types vonLiesegang-Ringen wurden untersucht. Verschiedene Systeme rhythmischer F?llung von Silberchromat wurden in einer Mischung von Agar und Gelatinegelen unter verschiedenen Umgebungsbedingungen erzeugt. Ringsysteme von Kupfer, Silber und anderen Ferricyaniden in Gelatine wurden untersucht. Die Beobachtungen zeigen, da? die Ursache für die „umgekehrten“Liesegang-Ringe in der hohen Peptisierbarkeit der Füllsubstanz im gelhaltigen Medium und den noch nicht reagierten Ionen liegt.相似文献
45.
Ohne ZusammenfassungÜbersetzt von Dr. K. Jäckel, Marburg/L.Wir danken Herrn Prof. N. R. Dhar D.Sc. (London und Paris), F.R.I.C., F.N.I., I.E.S. (Eetd) Direktor Shila Dhar Institut für Bodenkunde und Vorstand der Chemischen Abteilung, Universität Allahabad, für sein lebhaftes Interesse und seine Ratschläge für die Arbeit. 相似文献
46.
A new series of N-substituted bis-(tetrahydropapaverine) ring systems have been synthesised in expectation of better antispasmodic activity in comparison with papaverine. The synthesis of the targeted heterocycles is described along with a discussion of their structure activity relationship. The general synthetic methods of bis-(tetrahydropapaverine) analogues involve tetrahydropapaverine, various piperazines, diisocyanates and diisothiocyanates as starting materials. Pharmacological evaluation involves the in vitro antispasmodic activity on a freshly removed guinea pig ileum using a force displacement transducer amplifier connected to a physiograph. Among the analogues synthesized in the present study, N,N'-bis-[2-carbamoyl-1-(3,4-dimethoxybenzyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinyl]piperazine (22), was found to be the most potent muscle relaxant (IC(50): 0.31 microM). 相似文献
47.
Kundu S Pal A Ghosh SK Nath S Panigrahi S Praharaj S Pal T 《Inorganic chemistry》2004,43(18):5489-5491
Ligands with a beta-diketone skeleton have been employed for the first time as reductant to produce ligand stabilized gold nanoparticles of different shapes from aqueous HAuCl(4) solution. Evolution of stable gold nanoparticles follows first order (k approximately equal to 10(-2) min(-1)) kinetics with respect to Au(0) concentration. Growth of particles of different shapes (spherical or triangular or hexagonal) goes hand in hand under the influence of different beta-diketones, which have excellent capping and reducing properties. Chlorine insertion was observed to take place in the beta-diketone skeleton. 相似文献
48.
Kinetics of Bz2O2-initiated polymerization of VAC in pyridine at 60° were investigated. The polymerization was significantly retarded by pyridine. The monomer exponent decreased from 2.5 at a relatively low [Bz2O2] (1.0 × 10?2 M) to 2.0 at [Bz2O2] ? 4.0 × 10?2 M. The observed kinetic features were explained on the basis of degradative chain transfer and copolymerization with pyridine. 相似文献
49.
A reaction condition is established which determines the nature of the products in the molybdate-hydroxylamine-cyanide reaction. With hydroxylamine always used in excess, it is the hydroxyl ion concentration of the reaction mixture which plays a vital role in determining whether K4[Mo(NO)(CN)5] or K2[Mo(NO)(CN)5] is obtained exclusively. The latter product is hereby reported for the first time. Its powder diffractogram being typical of a cubic system, a gross structural characterization has been made possible. The former under aqueous, aerobic conditions yields a new product, (NMe4)2[Mo(NO)(CN)4]. 相似文献
50.
Premamoy Ghosh Partha Sarathi Mitra Amar Nath Banerjee 《Journal of polymer science. Part A, Polymer chemistry》1973,11(8):2021-2030
Low concentrations of bromine (0.008–0.06M) were used to initiate photopolymerization of MMA in bulk and in diluted (near bulk) systems, the diluents or solvents used being benzene, toluene, dioxane, tetrahydrofuran, carbon tetrachloride, chloroform, methylene chloride, and methanol. Polymerization in bulk follows usual free-radical kinetics. Inert solvents (benzene, toluene) as well as the other solvents used enhance the rate of polymerization MMA even when used in the range of catalytic concentrations (0.04–0.4M). An initiation mechanism involving solvent molecules appears to be predominant in diluted systems. 相似文献